Method of manufacturing an anode member for an x-ray tube

ABSTRACT

A method of manufacturing an anode member for an X-ray tube comprising the steps of preparing a cylindrical metal body with uniform thin thickness, inserting said metal body into a press mold in which at least one portion of its die hole is formed into a cylindrical shape and the other portion of said die hole assumes a polygonal cross section, inserting a cylindrical filler into the metal body, and applying pressure to the metal body through said filler to form part of the body into a polygonal shape in cross section.

United States Patent Seki et al.

[54] METHOD OF MANUFACTURING AN ANODE MEMBER FOR AN X-RAY TUBE [72] inventors: Yoshitaka Seki; Kaname Tanabe, both of Yokohama, Japan [73] Assignee: Tokyo Shibaura Electric Co., Ltd.,

Kawasaki-shi, Japan [22] Filed: July 7, 1970 [21] Appl.No.: 52,824

Related U.S. Application Data [63] Continuation-impart of Ser. No. 723,399, Apr' 23,

1968, abandoned.

[30] Foreign Application Priority Data Apr. 28, 1967 Japan ..42/27129 [52] US. Cl ..29/25.l8, 29/2511 ..H0lj 9/16, l-lOlj 9/44 [58] Field of Search ..29/25.l, 25.11, 25.13, 25.17, 29/25.l8

[ Feb.29,1972

[56] References Cited UNITED STATES PATENTS 1,406,542 2/1922 Crocker ..29/25.18 2,015,074 9/1935 Howland ..29/25. 17 2,795,033 6/1957 Cronin.... .....29/25.18 3,535,758 10/1970 l-loet ..29/25.18

Primary Examiner-John F. Campbell Assistant Examiner-Richard Bernard Lazarus Attorney-Flynn & Frishauf [5 7] ABSTRACT 3 Claims, 9 Drawing Figures Patented Feb. 29, 1972 2 Sheets-Sheet 1 FIG.

FIG. 4

FIG.

Patented Feb. 29, 1972 2 Sheets-Sheet 2 FIG. 7

FIG. 8

FIG. 9

METHOD OF MANUFACTURING AN ANODE MEMBER FOR AN X-RAY TUBE CROSS-REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of application Ser. No. 723,399 filed Apr. 23, 1968, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to a method of manufacturing an anode member for an X-ray tube.

The anode member of an X-ray tube in common use has been prepared by planing the outside of a raw block material such as copper and drilling its interior so as to form it into a cup shape and cutting out the specified portion of the cylindrical wall of said cup-shaped body in a square or circular form to provide a window. As described above, the conventional method involves planing, drilling and cutting, resulting in a complicated work process. Moreover, the planing and drilling work of reducing the wall thickness of the anode member is subject to certain limitations, minimizing said thickness to mm. at most. Since the interior of the anode member is also drilled into a cylindrical form, there likely occur irregular or excess wall thicknesses between the outer and inner cut planes, possibly rendering the anode member as a whole appreciably heavy. The great wall thickness of the anode member results in its increased heat capacity, requiring long hours of heating in brazing a beryllium plate to the X-ray radiating window. Further, there are presented difficulties in not only raising temperature but also effecting uniform heating. After the X-ray radiating window to which there is fitted the beryllium plate is sealed, one end of the anode member is further heated to elevated temperatures for fusion to a glass envelope. During said heating, the interior of the anode member is often subjected to oxidation and contamination, and various impurities are likely to be deposited on the focal plane of the anode member. Although grinding is required to remove such impurities, the integral and complicated structure of the anode member obstructs thorough cleaning. Moreover, it is difi'icult to carry out such decontamination to a desired extent for the efficient performance of an X-ray tube. When there is sealed a glass envelope to one end of the prior art anode member which is made of copper, it is necessary additionally to use a glass-scalable metal, leading to further complication of the manufacturing process.

SUMMARY OF THE INVENTION The object of the present invention is to provide a method of manufacturing an anode member for an X-ray tube which simply involves press work instead of planing, drilling and cutting as used in the prior art; more readily attains the elevated degree of vacuum in the X-ray tube using a cylindrical body of uniform thin thickness which is prepared from a glass-scalable metal in place of the raw copper block used in the conventional method; and enables the simultaneous formation by press work of a plurality of heat-radiating windows permitting the subsequent fitting of a beryllium plate. Namely, the manufacture according to the invention of an anode member for an X-ray tube comprises the steps of preparing a cylindrical body of uniform thin thickness from a glass-sealable metal; placing said cylindrical body and a filler member to be inserted thereinto together in a press mold; applying pressure to the cylindrical body through the filler member to press part of the cylindrical body into a polygonal shape in cross section; and boring given surfaces of said polygonal portion of the cylindrical body with through holes to form heat-radiating windows.

BRIEF EXPLANATION OF THE DRAWINGS FIG. 2 is a sectional view of a cup-shaped body into which the starting material of FIG. 1 is press worked;

FIG. 3 is a sectional view of a press mold in which there is placed the cup-shaped body of FIG. 2 together with a filler member;

FIG. 4 is a sectional view on line 44 of FIG. 5 of the shaped frames where there is applied pressure to the cupshaped body through the filler member;

FIG. 5 is a sectional view on line 5-5 of the press mold of FIG. 4;

FIG. 6 is a perspective view of a press molded anode member;

FIGS. 7 and 8 respectively are sectional views of the X-ray radiating windows; and

FIG. 9 is a side view of the X-ray tube with the anode member shown in FIG. 6, with parts of the tube broken away.

DETAILED DESCRIPTION OF THE INVENTION There is prepared a disc 11 shown in FIG. I, for example, 155 mm. in diameter by punching a l-mm. thick glass-scalable metal plate, for example, Kovar (commercial name of Westinghouse Electric Corp.), Femico (commercial name of General Electric Corp.) or Cov (commercial name of Toshiba) which consists of a material havingthe similar thermal expansion coefficient as glass. The disc 11 is subjected to the ordinary press-molding operation, for example, a four-step press-molding operation to be formed into a cup-shaped body 12 illustrated in FIG. 2. At the first step, the disc 11 is molded into a cup shape 95 mm. in diameter (a) and 40 mm. in height (b). Part of the open part of the cup-shaped body 12 is cut ofi", followed by the smoothing out of said cut open part. At the second step, the cup-shaped body 12 is reshaped into a form mm. in diameter (a) and 60 mm. in height (b) and then annealed l0 minutes at a temperature of 800 to 900 C. to eliminate the deformations or curvatures. The body is further press molded into a form 65 mm. in diameter and 75 mm. in height at the third step and finally into a form 57 mm. in diameter and mm. in height at the fourth step. Thereafter the body is again annealed 10 minutes at a temperature of 800 to 900 CfThe closed end of the cup-shaped body 12 thus worked is cut open to form a cylindrical body 13 having a uniform thin thickness, but this step may be omitted. The cylindrical body 13 is placed in a press mold 14. This press mold 14 comprises a first shaped frame 15 perforated with a cylindrical die hole which is fixed to a press base 17 by four bolts 16, a second shaped frame 18 perforated with a polygonal die hole such as an octagonal die hole which is concentrically disposed on the first shaped frame 15 and fixed to the press base 17 by four long bolts 20 penetrating the first shaped frame 15 and a third shaped frame 19 bored with a cylindrical die hole which is concentrically positioned on the second shaped frame 18. The inner diameter of the first and third shaped frames 15 and 19 is substantially equal to the outer diameter of the cylindrical body 13. The die hole of the second shaped frame 18 has the same octagonal shape as that assumed by part of the cylindrical body 13. While the aforesaid long bolts 20 are not required for press work, they are used to prevent the second shaped frame 18 from being carried along with a worked article when it is drawn out of the mold.

Into the cylindrical body 13 placed in the mold 14 thus constructed is further inserted a cylindrical filler member 21 made of, for example, polyurethane or rubber whose outer diameter is, for example, 1 mm. smaller than the cylindrical body 13. Without cutting out the closed end of the cup-shaped body 12, the filler member may be inserted into the cylindrical body before the latter is placed in the press mold. Then a pressure is slowly applied to the filler member 21 by a press 22 to a maximum pressure of 30 to 35 tons. This pressure so acts as to press that part of the filler member 21 which is received in the second shaped frame 18 together with the cylindrical body 13 toward the outside. (FIG. 5) Application of said pressure is carried out by the ordinary pressing technique using fluid, for example, an oil press. This pressure causes that part of the cylindrical body 13 which is positioned in the second shaped frame 18 to be formed into the same shape as the die hole of said second frame 18, that is, an octagonal shape. Thus is prepared an anode member 23 having an octagonal cross section, namely, eight flat planes on its peripheral surface. It is unnecessary to keep the anode member 23 under pressure for any specified length of time. One cycle of a pressing operation from the start to the release will be only about 1 to 2 minutes to fabricate the anode member. Upon release of pressure, the filler member 21 is brought back to its original cylindrical shape, and repeatedly used in manufacturing other anode members.

The anode member 23 and filler member 21 are taken out of the press mold 14 together with the third shaped frame 19. The upper and lower portions of the anode member may be cut off at a point removed upward and downward by a predescribed length from the center of the X-ray radiating windows later formed, if required, on the flat planes of the peripheral surface of the anode member 23. Said surface is bored with several through holes, such as four through holes 24 to form the X-ray radiating windows. (FIG. 6) Formation of these holes 24 is effected by drilling the required planes of the anode member 23 with its top and bottom ends securely clamped by separate means. The window is finished by soldering a beryllium plate to the through hole 24 so as to close it up. The operation of fixing said beryllium plate is conducted in the following manner.

Referring to FIG. 7, a ring-shaped auxiliary means 25 made of metal is mounted on a hole 24 perforated in the anode member 23, and a beryllium plate 26 is positioned on the platform section provided in the auxiliary means 25. While heating the entire assembly, there is poured silver solder between the anode member 23 and the auxiliary means 25 and between the beryllium plate 26 and said auxiliary means 25 so as to fuse them together.

The embodiment of FIG. 7 shows the auxiliary means 25 and beryllium plate 26 fitted to the anode member 23 at the same time. As shown in FIG. 8, however, it is permissible to use two auxiliary means 27 and 28, fit the beryllium plate 26 to the auxiliary means 28 in advance, and mount the assembly on the anode member 23 by the aid of auxiliary means 27. In this case, copper-silver solder may be used in fusing as in the embodiment of FIG. 7.

Other component parts of the X-ray tube shown in FIG. 9 are fitted as follows. A glass envelope 29 is directly fitted to the upper end of the anode member 23. To the inner circumferential surface at the bottom of the anode member 23 is directly fitted a ring member 30 by arc welding. On the inner circumferential surface of the ring member 30 is disposed a bottomed cylindrical anode head 31 coaxially with the anode member 23 and in such a manner that said bottom is projected into the interior of the anode member 23. The peripheral part of the opening of the anode head 31 fits in with the inner circumferential surface of the ring member 30 and is secured in place by brazing. The material of the anode head 31 generally consists of copper, and to the outer bottom side thereof, namely, the focal plane 32 may be fitted various types of target metal at the focal spot thereof.

The ring member 30 consists of such material as will enable it to be are welded to the anode member 23. However, in place of the ring member 30 assembled with the anode head 31 as shown in FIG. 9, said ring member 30 may be of such composition that only the peripheral edge thereof to be jointed with the anode member 23 consists of material capable of arc welding and the rest of the ring member 30 consists of the same copper part as the anode head 31.

Or the ring member 30 may be integrally formed with the anode head 31 using the same suitable material for the application of the present invention. ln either case there is sealed in the anode member a cathode 33 through the glass envelope 29.

The embodiment of the present invention constructed in the aforementioned manner has a great many advantages as described below. Namely, the anode member 23, which formerly consumed the largest amount of material among all parts involved and required complicated work, can be fabricated by press, so that it is of simple construction and permits quantity production. Also press work adopted in the present invention enables the thickness of the anode member 23 to be reduced, for example, to about 1 mm., thereby making easy the degassing of the anode member by hearing and raising the degree of vacuum of the X-ray tube.

With the conventional X-ray tube for analysis, the anode member had a large heat capacity, so that where a plurality of radiating windows containing a beryllium plate were brazed, the entire anode member had to be heated long. However, with the construction of the embodiment of the present invention, brazing can be carried out simply by heating the anode member 23 for an extremely short time. Further, the anode member perforated with through holes 24 to be used as X-ray radiating windows is fabricated by uniformly pressing the whole thereof. Therefore, where a beryllium plate is fitted to the radiating windows, it can be brazed thereto one by one, by heating only part of the anode member using a high frequency furnace. Accordingly there is obtained not only easier fitting work of the beryllium plate but also more stable brazing work than in the prior art process of brazing four radiating windows at once, for example. Namely, the present invention offers such advantages as were impossible with the conventional X- ray tube, for example, that if any of the four radiating windows should exhibit poor brazing work, then rebrazing may be performed to repair only that failing part. Moreover, the present invention can make great saving, because expensive beryllium can be surely recovered from bad products occur-ing in course of manufacture and there is no need to waste an expensive anode member as has been the case in the past.

At one end of a finished anode member 23 is sealed a cathode 33 through an electrically insulating envelope 29 made of glass or the like, and into the other end of said member 23 is fitted a bottomed anode member consisting of an anode head 31 and a ring member 30 and the peripheral edges of these components are jointed together by are welding, thereby to complete the assembly of an X-ray tube. In this case, the surfaces of the anode head 31 and ring member 30 which have a simple shape can be fitted very easily in advance either mechanically or chemically, and particularly impurities deposited on the focal spot of the focal plane 32 of the anode head can be surely removed. Further, the mixed impurities which present the greatest obstruction in applying an X-ray tube for analysis and also raise a serious problem with the product quality can be surely eliminated, because parts are fitted with the X-ray tube one by one so that the adjustment, correction, replacement or rebrazing thereof can be easily carried out each time need arises, so as to ensure a stable quality for the X-ray tube as a whole.

There has been described an anode member 23 in which that portion thereof provided with an X-ray radiating window is formed into an octagonal cylindrical shape. However, said portion may be shaped square or hexagonal by selecting the die hole of the second frame to assume the corresponding shape. Said anode member may be formed into a desired shape by using a given press mold.

What we claim is:

l. A method of manufacturing an anode member having a polygonal portion for use in an X-ray tube which comprises the steps of preparing a metal right circular cylindrical body of uniform thin thickness; inserting the right circular cylindrical body into a press mold in which at least one portion of its die hole is formed into a right circular cylindrical shape whose inner diameter is substantially equal to the outer diameter of said right circular cylindrical body and the other portion of said die hole is so formed as to be polygonal in cross section and have a plurality of flat planes; filling the interior of the right circular cylindrical body with a filler member; applying be subsequently assembled with other components to form an X-ray tube.

2. The method according to claim 1 wherein the filler member is made of polyurethane in a cylindrical form.

3. The method according to claim 1 wherein the thin-walled metal cylindrical member is comprised of a glass-scalable metal. 

1. A method of manufacturing an anode member having a polygonal portion for use in an X-ray tube which comprises the steps of preparing a metal right circular cylindrical body of uniform thin thickness; inserting the right circular cylindrical body into a press mold in which at least one portion of its die hole is formed into a right circular cylindrical shape whose inner diameter is substantially equal to the outer diameter of said right circular cylindrical body and the other portion of said die hole is so formed as to be polygonal in cross section and have a plurality of flat planes; filling the interior of the right circular cylindrical body with a filler member; applying high pressure to the interior of the right circular cylindrical body through the filler member to form part of the right circular cylindrical body into a polygonal shape in cross section which substantially conforms with that of the mold; removing the filter member from the cylinder and the cylinder from the mold; and boring the peripheral surface of the polygonal portion of the cylindrical body with a plurality of through holes to form X-ray radiating windows, said cylinder being adapted to be subsequently assembled with other components to form an X-ray tube.
 2. The method according to claim 1 wherein the filler member is made of polyurethane in a cylindrical form.
 3. The method according to claim 1 wherein the thin-walled metal cylindrical member is comprised of a glass-sealable metal. 